Brake discs of the aforementioned kind are known in the art. The friction ring therein includes rubbing surfaces on both sides. Following the friction ring, there extends, axially along the axis of rotation, a disc pot, and the disc flange extends in the radial direction from here.
The friction ring, the disc pot and the disc flange can be configured in pairs or, all three of them, in one piece with each other. They are manufactured, for example, as cast parts from soft gray cast iron or cast iron, respectively.
The disc flange therein includes, for example, a plurality of (threaded) bores that are distributed over the circumference thereof. Typically, they extend in the axial direction. The (threaded) bores serve for flange-mounting the disc flange to the wheel hub of the vehicle; typically, this is done by means of screws that are screwed into the threaded bores, for example.
Customarily, the flange facing of the disc flange as well as the flange facing of the wheel hub have a planar configuration, wherein both of the mentioned flange facings extend perpendicularly in relation to the axis of rotation.
When flange-mounting the brake disc to the wheel flange, a frictional closure is achieved between the two flange facings by the aforementioned axially disposed screwed connection, such that any moments occurring during the braking operation are essentially transferred to the wheel hub via the frictional closure in the contact zones.
To provide an adequate configuration of this frictional closure, particularly in cases when the brake disc are used on commercial vehicles, high tightening moments are applied corresponding to the size of the disc and the dimensions of the screws. Nevertheless, the eventuality that the frictional closure is insufficient, cannot always be precluded. If this is the case, due to the play between the interior wall of the bores that accommodate the screws, relative movements between the disc and the wheel hub occur, such as, for example, when high braking moments are in effect on the brake disc when changing from forward to reverse travel, such that the frictional closure is being neutralized.
Extreme compressive strains are generated, due to the high requirements that are demanded of the brake disc, particularly in the transitional area between the disc flange and the disc pot, meaning approximately in the radially interior area of the disc flange. If fastening is achieved with screws that extend inside bores, this critical area is usually radially inside with regard to the bore. As a consequence, increased wear and tear in form of partial and/or complete tears occurs primarily in the area of the internal radius of the flange facing of the disc flange.
Due to the limited available structural space, a reinforcement of the brake disc in the mentioned critical area, for example by an increased material use, is not possible. Moreover, such increased material use would also result in a corresponding weight increase.
Therefore, it is the object of the present invention to improve a bake disc of the kind as referred to in the introduction that also accommodates higher stress requirements associated with high braking moments while, simultaneously, only taking up a minimal amount of construction space and having only a minimal weight.